For Save Video plugin to capture the URL of the video and show the thumbnail, go to website like YouTube and start playback of the video.
Note: Internet Explorer 11 users - to enable Save Video plugin panel right click on IE window caption and select in context menu "Save Video (Toolbar Button)"

Please note that after the start of play, the file on the Save Video plugin panel of your Internet Explorer a thumbnail of this video appears. (see the screenshot) It means that the video is available for download.

Using your mouse, right click on the thumbnail of the video to activate the shortcut menu. In the menu which appears, click "Download Video ..".

Screen "Download Video". In this screen you can select a folder to save the downloaded video to. To do this, click "Browse" and select a folder. You can also create multiple categories such as "Music", "Photoshop tutorials" and assign these categories to folders on the disk. Then you can simply select a category to save the video in the desired folder. To edit a category, click "Configure".

If you want to convert the file into another format, check the "Convert" checkbox, then specify the output file format, for example AVI.

Click the "OK" button to begin downloading.

After downloading, click "Play" to play the downloaded file, or "Browse" to open the folder with the downloaded videos. Switch folder view in Windows Explorer toolbar to "Thumbnails" to see the thumbnails of the downloaded FLV files.

If the video you wish to download is available in more than one quality level then simply choose the desired quality level in the player. Save Video plugin will capture this request, obtain the valid URL, and display a thumbnail for each quality level of the video you request. (see the screenshot). On the thumbnails you can see the size of the video file, which tell you about quality of video.